1. Field of the Invention
The present invention relates to the field of personal computer (PC) conferencing. More specifically, the present invention relates to the cameras employed by PC conferencing systems.
2. Background Information
PC video conferencing systems are known in the art. Typically, under the prior art, PC video conferencing systems employ cameras that provide two modes of adjustments for the video image's brightness (i.e. exposure) and for color balance (i.e. daylight vs incandescent vs fluorescent). The two modes are automatic and manual. Under the automatic mode, the brightness and color balance are adjusted continuously to achieve an "ideal image", whereas under the manual mode, the brightness and color balance are adjusted under the control of the user. Most video conferencing systems are set up with the automatic mode as the default mode of operation. Some cameras provide a manual mode as the alternate mode if the user chooses to intervene.
This conventional approach was probably carried over from the general field of photographic cameras where the automatic mode is preferred by the overwhelming majority, i.e. the novice photographers, and the manual mode is preferred by the small minority, i.e. the sophisticated or professional photographers. This conventional approach worked just fine for photography applications, since there isn't a lot of disadvantage in having the photographic camera constantly adjusting for the "ideal picture".
However, the situation in video conferencing is different. Experience has shown that the overwhelming majority of video conferencing users do not want to intervene in adjusting the brightness and/or color balance of the video image. After all, the user's main business is to participate in the video conference in progress. As a result, most video conferencing cameras are left to operate in the automatic mode. While the background behind a video conferencing user remains typically unchanged, the foreground tends to be constantly changing because of the user's hand gesture as he/she speaks or because of the shuffling of papers referred to by the user, during the life of a video conference. These foreground changes cause the camera to continually adjust the image's brightness and color balance, which affects the brightness and color of the background Unfortunately, this kind of continuous changes has a significant disadvantage in video conferencing application. These changes in the background are interpreted as motion by the video compression algorithm, leading to a lower compression rate, and ultimately fewer video frames per second to the video conference user.
Thus, it is desirable to have a better approach for the camera function of a video conferencing system to adjust for brightness and color balance. As will be disclosed in the more detail below, the present invention achieves these and other desirable results.